1. Field of the Invention
This invention relates to a process for the production of alkene-1,5-diols. More particularly, it relates to a process for the production of a mixture of 3-methylene-1,5-pentanediol and the two geometric 3-methyl-2-pentene-1,5-diol isomers from the reaction of isobutene, formaldehyde and 3-methyl-3-buten-1-ol. 3-methylene-1,5-pentanediol has many uses in organic synthesis, and is particularly useful as a precursor for the production of citric acid, as taught in Belgian Pat. Nos. 784,238 and 792,076. Also, the alkenediols can readily be hydrogenated to alkanediols, which are useful in the production of polymers, resins, plasticizers and synthetic lubricants, and as chemical intermediates in the production of materials such as 3-methylvalerolactone.
2. Description of the Prior Art
It is known that an alkenol can be reacted with aqueous formaldehyde in the presence of a base to produce alkenediols. More particularly, U.S. Pat. No. 3,692,848 teaches the reaction of 3-methyl-3-buten-1-ol with aqueous formaldehyde at 235.degree. C. to 400.degree. C., thereby forming 3-methyl-2-pentene-1,5-diol.
Also, U.S. Pat. No. 2,798,996 discloses the reaction of anhydrous paraformaldehyde with mono-ol such as 3-methyl-3-buten-1-ol to produce the diol 3-methylene-1,5-pentanediol.
It is also known that alk-3-en-1-ols can be produced by the reaction of isobutene with aqueous formaldehyde. More particularly, U.S. Pat. No. 3,574,773 teaches the reaction of aqueous formaldehyde with isobutene in the presence of a base, forming 3-methyl-3-buten-1-ol.
Also, U.S. Pat. No. 2,335,027 discloses the reaction of diisobutene with paraformaldehyde to obtain a mono-ol, namely diisobutene carbinol.